The MJA does one additional thing that is worth noting but which I did not have space to address in Fortune: It pressures states to repeal their own marijuana bans. It does so by withholding a portion of federal law enforcement grants from prohibition states (and only prohibition states) if “the percentage of minority individuals arrested [or incarcerated] for a marijuana related offense in a [prohibition] State is higher than the percentage of the non-minority individual population of the State.” (The measure has similar language regarding treatment of low-income populations, but to simplify I’ll focus on racial minorities.)

The wording of the condition is somewhat opaque (raising its own set of problems), but let me illustrate how I think the condition would work in a hypothetical state with a 30% minority population. If minorities comprised more than 70% of those persons arrested or incarcerated on marijuana charges in that state, the state would lose some federal grant money going forward. If minorities comprised 70% or less of those arrested or incarcerated, the state would retain full eligibility for federal grants. The fact that this provision is aimed only at prohibition states (what the MJA calls “Covered States”) is why I say it pressures states to legalize marijuana: if a state does so, its federal grants are safe, even if it enforces any remaining prohibitions--say, on possession by minors--disproportionately against minorities. (This has happened in some legalization states, as in discuss in my book on pages 249 and 521).

I think this is an interesting and novel proposal to address race (and class) disparities in the enforcement of criminal law, and it deserves further consideration. But I think it also raises a handful of serious constitutional concerns (not to mention practical and political ones). Let me briefly flag just two of those legal concerns here.

One problem is that the MJA arguably fails to give states adequate notice of the new conditions it imposes on the receipt of federal grants. The problem arises from tying federal grant funds to the composition of the presently incarcerated population. The problem is that disparities in the racial composition of the incarcerated population undoubtedly stem from actions taken by the states in the past– i.e., before they were aware of the new condition. After all, many of those who are now serving time in state prison on marijuana charges would have been arrested and prosecuted years ago. Even though Congress can condition federal funds on states doing (or not doing) X, Y, and Z, it has to give them clear notice of those conditions in advance. E.g., Arlington v. Murphy, 548 U.S. 291 (2006). I’m not sure whether a condition that seemingly requires states to remedy past discrimination (e.g., by releasing inmates) would pass muster under this test.

A second concern is that the measure arguably amounts to reverse discrimination (or pressures states to engage in the same) in violation of the Equal Protection Clause. Return to my hypothetical state above, with a minority population of 30%. Suppose, fancifully, that this state arrested and incarcerated on marijuana charges only whites. Under the MJA, there would be no consequences for this state. In other words, the MJA only punishes a state if it discriminates against minorities. And the MJA would appear to pressure states to engage in reverse discrimination – for example, to keep its federal grant dollars, a state might have to release only minorities currently serving prison time on marijuana charges, or selectively target whites for marijuana arrests (so as to balance the ledger). Again, this approach might survive constitutional scrutiny, but it raises some doubts.

The simpler solution might be to preempt state marijuana bans. As I’ve argued elsewhere, that’s a permissible approach for Congress to take and would avoid the clear notice and Equal Protection concerns raised by the MJA.